Preparation for Hyperproperties

[h0nzZik]

New patterns:

• \member
• \subseteq

New strategies:

• contextual apply-equation
• propagate-predicate-through-application
• propagate-exists-through-application
• propagate-conjunct-through-exists

~TODO: documentation for strategies~

[nishantjr]

Please split this into multiple PRs each less than 10 commits.